Modern vehicles typically have a vehicle diagnostic system, including one or more separate computer control modules. Examples of such computer control modules (also known as just “modules”) are: a powertrain control module (PCM), an engine control module (ECM), a transmission control module (TCM), an ABS control module, and an air bag control module. Typically the computer control modules are connected together by a data link, forming the vehicle diagnostic system. The data link typically has a connection point, or data link connector (DLC) located in the cockpit of the vehicle. Typically the vehicle diagnostic system is used to proved relevant information to repair technicians. The DLC provides repair technicians with a place to connect off-board vehicle diagnostic devices, such as scan tools and code readers to the vehicle diagnostic system.
“Off-board devices,” such as scan tools and code readers are known in the art. Scan tool and code reader testing devices interface with vehicle diagnostic systems to, e.g., access, display, and/or print vehicle diagnostic information. OBD II (On-Board Diagnostics version II) Scan Tools are one commonly known type of scan tool and are governed by a number of standards, e.g., SAE J1978 Rev. 1998-02 and SAE J1979 Rev. 1997-09.
There are different types of scan tools. An “OBD II Scan Tool” complies with the above-identified specifications. By contrast, a “Manufacturer-Specific Scan Tool” is a scan tool that accesses and displays proprietary manufacturer-specific data (and possibly also additionally accesses and displays OBD II data). Examples of proprietary manufacturer-specific data include Device Controls on General Motors, On-Demand Tests in Ford, Actuator Tests, Sensor Tests, Interrogator, and Read Temporary Codes in Chrysler. In general, air bag data, ABS data, cruise control data, and climate control data are also considered to be proprietary manufacturer-specific data and are typically included only in Manufacturer-Specific Scan Tools.
Typically, scan tools are capable of performing at least some of the following major functions: “View Data,” also known as “Live Data,” “Data,” and “Data Test, DTC” (viewing and displaying in real-time live changing data from a plurality of module sensors), display of textual diagnosis descriptions corresponding to the various diagnostic codes, recording and playback of data, device control (manually controlling modules for diagnostic purposes), and reading and displaying vehicle information from the vehicle's computer (e.g., VIN information, controller calibration identification number, etc.).
Modern vehicles are generally equipped with numerous sensors, such as, for example, oil pressure, coolant temperature, transmission temperature, engine temperature, etc. Typically, most of the sensors are connected to a computer control module that continually monitors the sensors and regulates the vehicles functions accordingly. Generally the information generated by the sensor is continually passed along the vehicle data link as part of the vehicle diagnostic system. Thus, the scan tools are capable of reading, in real time, many parameters of the vehicle operation, such as, for example, speed, oil pressure, coolant temperature, engine revolutions per minute, and battery charging voltage because the parameters are continually updated and passed along on the vehicle data bus.
Many car enthusiasts, backyard mechanics, and hobbyists are not satisfied with the limited instrumentation, such as, for example, the number of gauges and warning indication lights, commonly referred to as “dummy lights,” that are standard features on many automobiles, and often desire to add additional display gauges to their automobiles. Examples of typical gauges that are added by car enthusiasts are tachometers showing engine revolutions per minute, oil pressure gauges, oil temperature gauges, coolant temperature gauges, coolant pressure gages, etc. Installing these additional gauges, however, can be a complicated endeavor.
Generally, the additional gauges are typically connected in one of two ways. In the first, the car enthusiast locates the correct wiring and splices the new gauge wiring into the existing sensor wiring. Locating the correct wires and following them to a convenient splice point is a difficult task and requires knowledge, time, patience, and skill that some individuals simply do not have. Moreover, this greatly complicates the task of writing comprehensive instructions because many models and makes of automobiles require individually tailored instructions to account for differences in diagnostic system configurations. In addition, if the splice is not correctly performed and properly sealed, the gauge will fail to work, and the connection between the sensor and the onboard computer may be degraded, resulting in the possible malfunction of that sensor, and possibly affecting operation of the internal combustion system. In addition, over time the splice connection might fail due to the constant vibrations within the automotive environment. The second common way to connect additional gauges is to add additional sensors to the automobile. Adding additional sensors is a complicated process, which involves mounting the sensor, connecting power to the sensor, and routing the wire to the new gauge. The skill that is required to perform this task is beyond that of many individuals. Therefore, there exists a need for a gauge display device that does not suffer the aforementioned deficiencies.